From mboxrd@z Thu Jan 1 00:00:00 1970 From: Krzysztof Kozlowski Subject: Re: [PATCH v9 05/20] PM / devfreq: Add new passive governor Date: Tue, 12 Apr 2016 09:30:34 +0200 Message-ID: <570CA41A.5050500@samsung.com> References: <1460347078-15175-1-git-send-email-cw00.choi@samsung.com> <1460347078-15175-6-git-send-email-cw00.choi@samsung.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: In-reply-to: <1460347078-15175-6-git-send-email-cw00.choi@samsung.com> Sender: linux-pm-owner@vger.kernel.org To: Chanwoo Choi , myungjoo.ham@samsung.com, kyungmin.park@samsung.com, kgene@kernel.org, s.nawrocki@samsung.com, tomasz.figa@gmail.com Cc: rjw@rjwysocki.net, robh+dt@kernel.org, pawel.moll@arm.com, mark.rutland@arm.com, ijc+devicetree@hellion.org.uk, galak@codeaurora.org, linux@arm.linux.org.uk, linux.amoon@gmail.com, m.reichl@fivetechno.de, tjakobi@math.uni-bielefeld.de, inki.dae@samsung.com, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, linux-samsung-soc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org List-Id: devicetree@vger.kernel.org On 04/11/2016 05:57 AM, Chanwoo Choi wrote: > This patch adds the new passive governor for DEVFREQ framework. The following > governors are already present and used for DVFS (Dynamic Voltage and Frequency > Scaling) drivers. The following governors are independently used for one device > driver which don't give the influence to other device drviers and also don't > receive the effect from other device drivers. > - ondemand / performance / powersave / userspace > > The passive governor depends on operation of parent driver with specific > governos extremely and is not able to decide the new frequency by oneself. > According to the decided new frequency of parent driver with governor, > the passive governor uses it to decide the appropriate frequency for own > device driver. The passive governor must need the following information > from device tree: > - the source clock and OPP tables > - the instance of parent device > > For exameple, > there are one more devfreq device drivers which need to change their source > clock according to their utilization on runtime. But, they share the same > power line (e.g., regulator). So, specific device driver is operated as parent > with ondemand governor and then the rest device driver with passive governor > is influenced by parent device. > > Suggested-by: Myungjoo Ham > Signed-off-by: Chanwoo Choi > [tjakobi: Reported RCU locking issue and cw00.choi fix it] > Reported-by: Tobias Jakobi > [linux.amoon: Reported possible recursive locking and cw00.choi fix it] > Reported-by: Anand Moon > Signed-off-by: MyungJoo Ham > --- > drivers/devfreq/Kconfig | 8 ++ > drivers/devfreq/Makefile | 1 + > drivers/devfreq/governor_passive.c | 207 +++++++++++++++++++++++++++++++++++++ > include/linux/devfreq.h | 33 ++++++ > 4 files changed, 249 insertions(+) > create mode 100644 drivers/devfreq/governor_passive.c > Acked-by: Krzysztof Kozlowski Best regards, Krzysztof